Generation of gear teeth



Deve. 18 1923." 1,478,188

H. E. TAYLOR GENERATION 0F GEAR TEETH originalfiled July 24. 1928 2sheets-sheet wazig/,TOR I ffl-@M .flTTvoR/VEY atented Dec. l, i223, l

nai-'ran stares navrant erste/a,-

HERBERT'EDGAR TAYLOR, 0F COVEN'IYRY, ENGLAND.

GENERATION OF GEAR TEETI-I.

Original application filed July 24, 1923, Serial No. $53,453. Dividedand thisiapplcation filed October 17, 1923. Serial No.. 668,969.

To @ZZ whom t may 00a-cera: ln carrying out the invention, the arm A,

Be it known that I, HERBERT Encan by means oiz the shaft A2 is pivotallymount- 55 TAYLOR, a subject of the King of England, ed upon a fixed partB, which latter, howresiding` at Covent-ry, in the county of Warever,isv adjustable in relation to the axis ot 5 wick, England, have inventedcertain new the blank to be acted upon, Lengthwise and usetulImprovements in the Generation upon the arm A are guide members A3 forol Gear rleeth (for which l have: filed in a slide C on which aremounted the tool 60 Great Britain application No. l99,463, dated holderC2 and tool D of rack form. he

March 22, 1922), of which the following is a direction ot motion of theslide C is lengthspeciication. wise of the arm A, that is, radially ofthe `This invention relates to the generation pivot axis, and itsrelative sliding moveof those gear teeth which extend in inv'clute mentsare controlled by means ci a cam car'- 65 curves along the'blank and areot uniform ried bythe xed part B and engaging a stud f normal pitchvfrom end to end as described in or roller C3 or the like, on the slideC.

my application, Ser. No. 653,453, filed July Any suitable type of cammay be adopted 24, 1923, of which this is a division. The obto controlthe movement of the slide radially ject of he invention isto provide animand in the construction illustrated it is` con- 70 proved method ofgeneration. stituted by the Aformation of a suitably The inventioncomprises a method for curved slot E2 in a plate E which is carriedgeneratin 0 O'ear teeth fora'gear system havby the fixed part B' in aplane parallel to v Ab c l u n n ing as its basis a crown wheel whoseteeth that 1n which the arm A swings, and is inextend along involutevcurves and are ot terehangeable with other equivalent plates uniformnormal pitch Jfrom end to end, and arranged to suit the various sizes ofgears consists in rolling the gear blank in the path to be cut, and inaccordance with the disit would follow if meshed with the said tance ofthe pivotal axis of the arm A from basic crown wheel, while acting uponit by the axis of the blank upon which the tool means of a tool of rackform which sweeps B acts. The roller C upon the slide C en- 80 out aninvolute curve Corresponding` to the gages in the cam slot E2 andensures positive curve of the teeth on said basic crown wheel.reciprocations ot the slide, and preferably, Prefembly the e001 i5@a1-fied by a Slide although a simple roller C3 is shown, its armovablealong an arm which oscillates about rangement would be of a known kindVadapta xed point, during which oscillation the ed to avoid a grindingeffect on the cam. @5 slide is acted upon by a cam which varies the twill be seen that the curved slot E2 dit'- acting radius of the tool insuch manner ters but slightly from the arc of a circle inasthat, insteadof moving in the are of the cirmuch as the axis of the shaft A2 iSlocated at cle, it traces out the desired involute path. a position suchthat a curve struck from For cutting double involute gears two of itwould conform very closely to the inthese slides are employed, and whenapprovolute curve which it is desired to produce. priately mounted forma double cutting A slight stop is provided at E3 in the cam 14) head,each slide being actuated by approslot, and the portion seen to the leftof this priate mechanism. in the drawing is the acting part which Themanner ot carrying out the invention forms the involute curve, while theportion is illustrated in the accompanying drawings, to the right is anextension concentric with in which the axis of the shaft A2 and merelyprovided Figure l is a front elevation of the tool to allow for theswing of the arm At.

holder, the point of the tool moving in a To operate the slide-carryingarm A, it is plane parallel to the paper. extended upon the side ot apivot A2 remote Figure 2 is a part-sectional side elevation from theslide C, and for constructional reaof Figure l, sons this extension isseparate from the arm Figure 3 is a part plan view as seen from A andVis constituted by another arm A4 fixed above, and to the shaft A2 atsome distance from the slide Figure 4 is a view similar to Figure l, C.At the free end A5 of the arm A4 it is but showing an alternative formof cam. connected by means of a link (not shown) to -any appropriateform of driving mech@ anism. Y l e The tool with `its actuatingmechanisn is adapted to be used upon a machine in which the blank isarranged to rotate upon its own aXis and also to perform a rollingmotion around an axis corresponding to that of the standard crown wheelor equivalent thereofY with which it would be adapted to gear.

The embodiment of the invention as above described is of a simple formand can be constructed in a sturdymanner adapted to reduce wear and toavoid slackness, and is suitable for CuttingY single or double involutegears i. e., those in which the teeth incline one way only, or two waysforming chevrons) but it is to be understood -that the manner ofoperating the slide andthe arrangement Vof the mechanism therefor is notlimited to the construction above described.

Thus, for example, as shown 1n Figure t, the cam may be constituted byan annular disc F coaxial with the point of oscillaticn of the arm A,and the acting part of its outer periphery may be shapedv in the mannerabove described for the curved slot E2. Rollers Gr, G2 upon the slide Cwould engage opposite sides of the cani F to cause the movement of theslide, and one'of these rollers G2 would be pressed by the spring G3against the cani to Vfollow up the movements of the slide and prevent'any ,shake in it. y Y

XVhere double involute teeth are to be cut, two oscillatingtool holders,as above described, are employed, one to thek eii'ect the Vpart of thetooth having the right-,handed sweep,v and therother for the left-handedsweep,l cach holder .being located about an appropriate axis ot'oscillation to effect this. The movementy of both tools would be timedso that they and their tool slides cleared one another throughout theirrespective travels. Y

What I claim as my invention and desire to secureLetters Patent of theUnited States Y l. The'r method ofV 'Generating bevel Gear b C 2D teeth,the sides of which describe Vcurves on' the pitch cone, which consistsin giving a tool, having the shape of a tooth of the basic crown gear ofthe system, an oscillatory'cut-v ting motion across the face of theblank and simultaneously moving` said tool towards and away from itsaXis of osciliatiomwhile giving the blankthe rotary and rolling motionsa tool, representing a tooth of said crown gear, an oscillatory motionat right angles to said curves and simultaneously varying.

the radius of said oscillatory motion to cause the toolto follow saidcurves instead of circular arcs.

3. rlhe method ocutting bevelgears dac# cording to the generating systemand soV that the teeth are longitudinally curved Vacross the face of theblank in other than circular arcs and are of uniform normal pitch 'fromend to end, which consist in giving the blank, in addition to a rotationon its own axis, a rolling motion'about the axis of theimagif nary crowngear forming the basis of the-A system to which the gear being Vcutbelongs, and givingthe tool,which has the shape of the teeth or saidimaginarycrowngear, an oscillating cutting motion across the 'aceot theblank and simultaneouslyvarying the length of thel radius ofoscillation.V

In testimony whereof I aihx mysignature.

HERBERT EDGAR, friiYLoa.

